Furmark/synthetic testing. It maxes out your GPU so you can see how it is performing at full load. If your rig melts when the GPU is not frame limited and running at full tilt then it is clearly a warranty replacement due to defective hardware or PEBKAC for the builder/overclocker who tried to get away with too much.

There seems to be a story every time a major games comes out. GTA IV RRoD'd my 360, Uncharted 3 bricked my PS3, Crysis melted my gaming rig. The defects show up when millions get together to spend many extra hours using any hardware at full kilter. Yes, SC2 could do a better job of limiting the menu code to only render to the frame-rate cap (which I note is in full 3D and so really your v-sync options should come in and mean your GPU isn't overworked) but any failure is a hardware one, pure and simple.